Nubia WD660 Replacement Battery BM600 3.7V 1800mAh

Nubia WD660 — 3.7V Li-ion Replacement Battery (BM600)

This is a 3.7V 1800mAh Li-ion battery for the Nubia WD660 portable Wi-Fi hotspot. It replaces OEM part BM600 and alternate reference 6BT-R600A-0006. When the original cell degrades and the hotspot can no longer hold a session, this swap restores full capacity without replacing the unit.

• WD660 hotspot platform: The WD660 runs a combined cellular modem and Wi-Fi radio off a single 3.7V cell. Both radios draw simultaneously whenever clients are connected, so the BMS in this battery is matched to that dual-load profile — it won't trip on the current spikes that occur when new clients join the network.
• Bench tested on actual hardware: We cycled this cell under a simulated multi-device load — modem active, Wi-Fi radio at full output. The BMS held voltage without dropping into low-voltage cutoff during peak draw, and cell temperature stayed within normal operating range throughout the session.
• Ventilation during extended sessions: Keep the WD660 on a hard, open surface when running for long periods. When connected devices are far from the hotspot, the cellular radio runs at maximum transmit power — this raises internal temperature and accelerates cell wear if the unit is pocket-carried or placed face-down.

Why the WD660 drops connections mid-session under full client load

The WD660 modem and Wi-Fi radio both spike current draw when handling multiple active clients — streaming, file transfers, and new device handshakes all hit at the same time. An aged or degraded cell can't sustain the voltage rail through that combined surge, so the BMS triggers a brief cutoff to protect the cell. Users see this as a sudden disconnect or a hotspot that briefly disappears from the Wi-Fi list. A fresh 1800mAh cell with a healthy internal resistance handles the surge without dropping below the BMS cutoff threshold.

WD660 won't power on after sitting unused for several weeks

Li-ion cells self-discharge slowly in storage, and the WD660's standby circuits continue drawing a small current even when the unit appears off. After several weeks, the cell can fall below the minimum boot voltage — typically around 3.0V — at which point the BMS locks out the discharge path entirely and the power button produces no response. Plug the unit into its charger and leave it for 20–30 minutes before attempting to power on; if the charge LED activates, the BMS has re-initialized and charging has resumed. If no LED appears after 30 minutes, the original cell has dropped below recovery threshold and replacement is the correct next step.